2.9BSD - /usr/src/lib/libF77/c_sqrt.c

   1: /*
   2:  *	"@(#)c_sqrt.c	1.1"
   3:  */
   4: 
   5: #include "complex"
   6: 
   7: c_sqrt(r, z)
   8: complex *r, *z;
   9: {
  10: double mag, sqrt(), cabs();
  11: 
  12: if( (mag = cabs(z->real, z->imag)) == 0.)
  13:     r->real = r->imag = 0.;
  14: else if(z->real > 0)
  15:     {
  16:     r->real = sqrt(0.5 * (mag + z->real) );
  17:     r->imag = z->imag / r->real / 2;
  18:     }
  19: else
  20:     {
  21:     r->imag = sqrt(0.5 * (mag - z->real) );
  22:     if(z->imag < 0)
  23:         r->imag = - r->imag;
  24:     r->real = z->imag / r->imag /2;
  25:     }
  26: }

Defined functions